Party-line telephone system.



E. D. WILHS,

PARTY LINE-TELEPHONE SYSTEM.

APPLICATION FILED NOV- 13, 1906.

Patented @1213, 1915,

i are nnnNnnco n. WILLIS, or on'rcaeo, ILLINoIS, AssIeNon, er r/INsNnASSIGNMENTS, ro

- rrnsr raus'r AND SAVINGS BANK, reverse, or CHICAGO, ILLINors.

PARTY-LINE TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented nan raters,

Application filed November 13, 1906. Serial No. 343,213.

toms, of which the following is a spec1fica-' tion.

My invention contemplates an improved arrangement for preventingllllZGI'TBIGIlOB between party line subscribers in an automatictelephone exchange systemor in any system, automatic or manual orsemi-auto- 1naticen'1ploying operating grounds at the substations.

The accompanying drawing is a diagram showing two substations of myimproved type connected to a line leading to an automatic centraloffice.

The substation A is shown in an oper' ated position, while thesubstation A is shown in normal position. The groundcontrolling relay isshown in an energized condition at E. tor Q and a first-selector D arelocated at the exchange, the latter allotted to the line of substationsA and A. A central battery is shown at B having its positive terminalpreferably grounded at G. The ringing and busy signaling machines Hand Tare located in the central exchange.

The substations comprised in my in vention may be of any suitable orapproved typ. The substation A comprises a receiver 2, a switch-hook 3for controlling the substation circuits, which controlling operationsare accomplished through the medium of any suitable means such as thecam arms 1, 5 and 6. The said substation comprises the usual transmitter7, inductioncoil Shaving the primary Winding 9 and secondary winding 10;the ringer 11, and the condenser 12 in the ringer circuit. Being anautomatic substation it is provided with the usual vertical and rotaryimpulse springs 13 and 14 and with the release springs-1.5, 16 and 17.Said substation is, of course, provided with a dial which is not shownbut which is secured to the shaft 18, together with the locking dog 19.Further more. there is a locking cam .20 that locks the A dog 19 whilethe receiver is on the switchhook to prevent a rotation of the dial, The

substation ground circuit extending from the ground-controlling relay Eisnormally broken between the ground springs 21 and A common batteryconnec- 22 by the cam arm d; but when said springsare permitted toengage, ground connection is then provided to the ground post 23 and totherelease spring 17, as is Well known in telephones of this type. Foroperating the impulsevsprings 13 and 14: the substation is provided withan impulse wheel 24 that is secured to the shaft 18, which wheel carrieson its periphery the so-called vertical impulse teeth 25 and one rotaryimpulse tooth 26. The said impulse teeth are so arranged that when thedial is drawn down the impulse springs 14 and 13 are not carried intocontact with the ground post 23;

but as the dial returns, first the vertical teeth engage the verticalimpulse spring 13, and after they have completed their work the rotaryimpulse tooth 26 operates the rotary impulse springlt. In this operationthe subscribers vertical line conductor 2 7 is first given a number ofground impulses, and then the rotary line conductor 28 is given oneground impulse. lit will be noticed that as long as the dial is out ofnormal position the construction is such that the dog 19 permits theprimary circuit springs 29 and 30 to separate, thus preventing theimpulses that are delivered to either line conductor from passing, tothe other. Furthermore, when the switch-hook 3 is down the cam arm 5presses the spring 31 out of engagement with the spring 32, whereby theprimary circuit is opened. Also, in the downward stroke of theswitchhook 3, the release springs 15, 16 and 17 are momentarily pressedinto engagement by the cam arm 6. The springs 33 and 34: are socontrolled by the cam t that when the switclrhook risesthe said springsare pressed into engagement. The signaling device comprises-the button35 which when pressed carries the spring 36 out of engagement with thecontact point 37 and into en-.

disengages from the contact point 43, breaking the groundcircuit for allthe telephones along the line, so that no substation will be grantedMarch 13, 1906, toKeith, Erickson and Erickson. The connector is animrovement on the connector disclosed in atent N 0. 815,176, grantedMarch 13, 1906, to Keith, Erickson and Erickson. My invention is notparticularly concerned with the-connector C except in a general waythatis, since the substations are of the common battery type the connector Cmust be one,adapted to common battery work. I have, therefore, electedto disclose my invention in connection with the connector C which/hasbeen disclosed in United States patent application Serial No. 294,663.It will be suificient to simply explain that the line relays 61 and areconnected directly to the conductors and 76 and in multiple to oneterminal of the non-grounded terminal of battery B until after a calledsubscriber answers. When the called subscriber answers, the back-bridgerelay 72 is adapted to energize and shift the connections so as tobridge the battery B between the line relays 61 and 70 for supplyingtalking battery to the calling line.

The operation ofmy improved telephone for example, 7 "that thesubscriber at substation A desires system is as follows: Assume,

to establish connection with some other subscriber. He removes thereceiver 2 from the switch-hook 3 and operates the dial in thewell-known manner for each digit, as a result grounding the vertical androtary lin'e conductors 27 and 28, respectively, whereby g1?)first-selector D and in turn the connector ner. When the subscriberremoves the receiver 2 from the switch-hook 3 the said hook rises andthe cam arm 4 presses the springs 33 and 34 into engagement, whereby anenergizing circuit is closed through the rela E, which circuit extendsfrom ground through the coil 39, conductor 45, contact springs and 34,then through the springs 29 and 30 to the vertical line conductor 27,side switch wiper 46, contact point 47, vertical line relay 48 of thefirst-selector D, bridge-cut-oii tery lead 51, thence through battery Band to ground G. The relay E upon energizing operates, as previously.explained. Now when the subscriber at A turns the dial the lockin dog-19is raised and the springs 29 and 30 disengage, thereby breaking theenergizing circuit through the relay E. The

armatures 40 and 41 then return to their normal position in engagementwith the contact points 42 and 43, respectively. On

the return motion of the dial the impulseecome operated in thewell-known manpoint 37 and spring 36, through they springs 49 and 50 tothe bat the first-selector D in the well-known nanner. The energizingcircuit of the vertical relay 48 extends from ground G, contact point43, through the armature 41, conductor 53, ground springs 21 and 22,ground post 23, vertical impulse spring 13, vertical line conductor 27,side switch wiper 46, contact point 47, vertical relay 48,bridge-cut-ofi springs 49 and 50 to the battery lead 51,

thence from battery B to ground G. The" energizing circuit through therotary line relay 52 extends from ground G, contact point 43, throughthe armature 41, conductor 53, ground springs 21 and 22, ground post 23,rotary impulse spring 14, conductors 54 and 55, contact point 42,armature 40, rotary line conductor 28, side switch wiper 56, contactpoint 57, rotary line relay 52, bridge-cut-off springs 58, 49 and 50 tothe battery lead 51, thence through battery B and to ground G, After thefirst-selector D has operated and the side switch passes to thirdposition, the line conductors 27 and 28 are extended to the connector C.At the same time the energizing circuit through the relay E is againcompleted when the dial comes to rest and the springs 29 and 30 againengage. This time the energizing circuit is extended to the connector Cas follows: From the side switch wiper 46 to contact point 59, shaftwiper 60, connector vertical line relav 61, through the winding lead 51,thence through battery B and to ground G. From the foregoing it is,there fore, obvious that the relay E is energized as soon as theswitch-hook 3 rises sufiiciently for the cam arm 4 to press the springs33 and 34 into contact. Now when the dial is rotated in the course ofcalling a number the energizing circuit of the said relay is broken andthe armature '41 falls back onto the grounded contact point 43, wherebythe ground post 23 is provided with ground for grounding the verticaland rotary line conductors,'as explained; but as soon as the dialreturns to normal position the energizing circuit is again completed andthe ground G" is again removed from the conductor 53. Hence, afterthesubscriber remoyes his receiver preparatory to calling a number andthe switch-hook 3 is up, the only time that there is a ground connectionat the substations A and'A occurs while the dial is out of normalposition and consequently while the .springs 29 and 30 are out ofengagement. The" subscriber at substation A may thus seize and hold theline with minimum danger of interference from the substation A by theoperation of the dial or signaling insects button, or by pressing therelease springs into engagement upon the restoration of the receiver.

lit will be noticed that the talking circuit extending from thesubstation A to the rotary line conductor 28 is slightly different fromthe calling circuit to the same conductor. tion A extends from thevertical line conductor 27 through the primary Winding 9, transmitter 7primary springs 32 and 31, contact point 44, armature 40 to the rotaryline conductor 28; while the calling circuit reaches the rotary lineconductor through the contact point 42 and conductor 55, as explained.The release of the central office apparatus may be brought about bygrounding both line conductors 27 and 28 simultaneously, as is usuallythe case. My invention is arranged for this kind of release. When thesubscriber restores the receiver 2 to the switch-hook 3, the saidswitch-hook immediately starts on its downward course, and before theswitch-hook has moved very far the cam armhas removed sufficiently toallow the springs 33 and 34:- to disengage, thereby breaking theenergizing circuit through the relay E, whereby the ground G is again inconnection with the conductor 53. Then upon the engagement of therelease springs 15, 16 and 17 the vertical and rotary line conductors 27and 28 areagain grounded simultaneously. The said ground circuit extendsfrom ground G, through the contact point 43 and armature 41, conductor53,

through the ground springs 21 and 22 to the ground release spring 17,then through the springs 16 and 15 to the vertical line conductor 27.The ground to the rotary line conductor extends from the ground releasespring 1.7 to the spring 16, conductor 54, conductor 55, contact point42', armature 40, then to the rotary line conductor 28. Both lineconductors 27 and 28 being grounded simultaneously, the central officeswitches employed by the said line are released. The release may, of'course,-take place either before the seletor has trunked to theconnector C or aft .r. In the first case, when the vertical and' rotaryline conlays 61 and 70 energize simultaneously, the

trunk-release springs 71 and 72 are brought into contact, and atrunk-release circuit is established comprising in series the releasemagnet 73 of the connector C and the back The talking circuit at thesubstarelease relay 74-. of the first-selector D. The energization'ofthe release magnet 73 of the connector (3 produces the restoration ofthe connector side switch and switch-shaft in a manner disclosed in thesaid connector patent. The energization of the back-release relay 74 ofthe selector D causes the release of the first-selector in the mannerdisclosed in said selector patent, the release circuit of which isdestroyed when the grounding of the line conductors 27 and 28 isterminated and, therefore, when the line relays 61 and 70 of theconnector C deenergize.

My invention is designed to operate as Well when the line iscalled aswhen calling, to open the substation ground circuit after a subscriberthereon comes in on the line. There are certain classes of connectorswhich are so constructed that, with ordinarypartylines, the establishedconnection may be released if a second subscriber comes in on the calledline and grounds the same; and it is also for preventing this that myinvention has been worked out. Assuming, therefore, that the line shownin the drawing is called, the connection is established as usual overthe normal conductors '64: and 66 by the calling connector. Thesubscriber who answers (subscriber A for instance) energizes thecut-off" relay E as soon as the springs '33 and 34 are carried intoengagement, as previously explained, and over a circuit comprising oneof the so-called back-bridge relays 7 2 to battery B. Therefore, theground G is temporarily cut oil from all the substations on the line.The condenser is provided in order that the tapping of the bells 11 and67, and any other bells across the line, may be minimized when impulsesare being delivered to the line when another subscriber is calling.

The automatic switches can be arranged on a percentage basis, so as tobe less in number than the subscribers, and so as to afford automatictrunking between the lines of an exchange in which provision is made forremoving the ground from all of the substations on a line as soon as oneof the party-line subscribers takes down his receiver.

What I claim as my invention is 2- 1. In a telephone exchange system,the combination of automatic means for trunking between calling andcalled subscribers, a telephone line, a plurality of substations on saidline, subscribers switch-hooks, telephones on said switch-hooks, aground connection common to all of said substations,

substation calling devices for utilizing said ground connection 1nsending ground imipulses over the line to operate said automatic trunkmmeans a rela for severin the ground connectlon, and means forenergizingsaid relay by'the taking down of any telephone.

2. In atelephone exchange system, the combination of automatic means fortrunking between calling and called subscribers, a telephone line, aplurality of substations on said line, subscribers"switch-hooks,telephones on said switch-hooks, a ground'connection common to all ofsaid substations,

' substation calling devices for utilizing said ground connection insending ground impulses over the line to operate said'automatic trunkingmeans, a relay for severing the ground connection, means for energizingsaid relay by the taking down of any telephone, and common battery meansfor supplying current to the said line for both trunking and talkingpurposes.

3. In a telephone exchange system, the combination of a telephone line,a plurality of grounded substations on said line, switchhooks at saidsubstations, telephones on said switch-hooks, and automatic means fordisconnecting all substations from ground by, the taking down of anytelephone.

4. In a telephone exchange system the combination of a telephone-line, aplurality of grounded substations on said line, switch hooks at saidsubstations, telephones on said switch-hooks, automatic means fordisconneeting all substations from ground by the taking down of anytelephone, and a central batteryor source for supplying current to thesaid line for talking purposes.

5. In a telephone exchange system, the combination of a telephone line,a plurality of grounded substations on said line, switchhooks at saidsubstations, telephones on said switch-hooks, automatic means fordisconnecting all substations from ground by the taking down of anytelephone, and a central battery or source for supplying current to thesaid line for talkingpurposes, said automatic means including aground-controlling relay common to all of said substations.

6. The combination of a subscribers calling dial, a ground connection, aground-controlling relay, a switch-hook for controlling the energizingof said relay, means by which the operation of said dial deenergizessaid relay, and means by which the relay is reenergizedby therestoration of the dial to normal position. I f

7. In a telephone system, a {party-line, a plurality of groundedsubstations on the line, arelay controlling the continuity of the line,adapted also to control the continuity of the connection to ground fromthe substations, and means for energizing said-relay to close the lineand disconnect the substations from the ground whenever any subscriberon the line takes down his telephone.

8. In a telephone system, a party-line normally open at one pointtherein, a plurality of substations 'on said line, a relay common to allof said substations and controlling the said normally open point in theline, a connection to ground from each substation normally closed bysaid relay, and means for energizing said relay to cut oif the groundand close the line whenever any subscriber thereof any telephone, saidtrunking means including switches having motion in one plane to selectgroups, and motion in a plane at right-angles thereto to find a line inthe selected group. I

10, In a telephone exchange system divided into groups, the combinationof automatic means for trunking between calling and called subscribers,a telephone line, a plurality of substations on said line, subscribersswitch-hooks, telephones on said switchhooks, a ground connection commonto all of said substations, substation calling devices for utilizingsaid ground connection in sending ground impulses over the line tooperate said automatic trunking means, a relay for severing the groundconnection, means for energizing said relay by the taking down of anytelephone, and common battery means for supplying current to the saidline for both trunking and talking purposes, said trunking meansincluding switches having motion in one plane to select groups, andmotion in a plane at rightangles thereto to find a line in the selectedgroup.

11. In a telephone system, a subscribers line having a plurality ofsubstations thereon, a subscribers calling dial at each substation, aground connection common to all of said substations, aground-controlling relay,

a switch hook at each substation for controlling the energizing of saidrelay, means by which the operation of a dial deiinergizes Said relay,and means by which the relay is reenergized-by the restoration of thedial to normal position.

' Signed by me at Chicago, Cook county, Illinois, this 8th day ofNovember. 1906.

BERNARD D. WVILLIS. Witnesses:

EDWARD D. FALES, ARTHUR B. SPERRY.

